Current glucose

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark readOnlyHint=true, but the description adds critical behavioral context: the value is not a live reading, the measured_at timestamp must be used, and the tool is informational only and not for medical treatment decisions. This goes well beyond the structured annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, each serving a distinct purpose: stating what the tool does, warning about the timestamp semantics, and adding the safety disclaimer. No redundant or vague wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read tool with no output schema, the description covers the essential semantics: the return includes the value and measured_at, the data may be stale, and there is a safety caveat. This is sufficient for an agent to invoke and interpret the result correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema fully describes the single 'unit' parameter with enum, default, and meaning ('Storage is always mg/dL; this only affects display'). The description does not add any parameter-specific details, so baseline 3 applies per the rubric.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Read' and the resource 'most recent glucose measurement from the FreeStyle sensor', with the additional detail 'with the instant it was actually measured'. This distinguishes it from the sibling tool get_glucose_history, which presumably returns historical data.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear context on when to use the tool (to get the latest upstream value) and gives important usage guidance: do not treat it as a live reading and always report measured_at rather than 'now'. However, it does not explicitly mention get_glucose_history or state when not to use this tool, so it lacks explicit exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.